In containers with collapsible pouring spouts, the container is usually made from a relatively stiff material, such as sheet metal or HDPE, and the spout from a softer material, such as LDPE. The spout therefore has to be joined to the container in a reliably strong and preferably leak-proof way. Here the flexibility of the spout leads to difficulties, since those parts of it forming a joint with the container are easily deformed and so can be dislodged from the container, unless special measures are taken. Similarly, the flexibility of the spout material means that it is difficult to obtain a tight interference fit and a reliably energised seal at the spout/container joint. A known solution to this problem is to provide an end portion of the spout which peripherally overlaps a neck of the container, and a metal ring crimpable around the outside of the overlap so as to form a firm mechanical joint and energised fluid seal. Often the container neck will have an outwardly projecting circumferential rib or the like, and the joint-forming part of the spout a complementary inwardly projecting rib or the like, received beneath the neck rib and locked in engagement with it by the crimped ring. The resulting joints are satisfactory but use of a separate metal ring adds to expense and parts inventories, as well as making recycling more difficult. Metal rings can also be prone to corrosion. It is not readily possible to make such a crimpable ring from plastics material instead of metal, due to the differing elastic properties and yield point of plastics compared to the metals which are commonly used to form the crimpable ring, e.g. steel. Metal constrictable rings are also known for securing removable lids to pails and drums.
All-plastics closures for containers with flexible plastics spouts are known, in which the crimpable metal ring is replaced by a plastics ring or band, which is configured to snap-fit onto the container neck as an assembly with the joint-forming part of the spout. When so fitted, the plastics ring acts to force the end of the flexible spout into tight engagement with the container neck. The ring or band may comprise an outer circumferential part of the closure, made in one piece with a central part which forms a closure fitted to the tip of the spout, e.g. by a screw threaded connection. The central closure part can be pulled out from the outer circumferential part so as to extend the spout, then allowing the central part to be unscrewed or otherwise removed from the tip of the spout so that the container contents can be dispensed. The outer circumferential and central parts are typically joined by frangible links. The central part will often be provided with one or more bail-type handles, which can be raised and gripped to aid the central part pull-out and unscrewing etc. operations; the frangible links extending between the bail-type handles and the outer circumferential part. Such a container closure is disclosed for example in EP0320808, in which the outer circumferential part is forced axially downward relative to the central part during fitment of the closure and spout assembly to the container. This breaks the frangible links, which therefore cannot provide tamper indication.
Alternatively it is known to provide an outer circumferential part which does not move relative to the central part during installation of the closure and spout assembly on the container. Frangible links between the bails and the outer circumferential part therefore can remain intact during fitment of the assembly, as disclosed for example in U.S. Pat. No. 5,797,525. These links are broken when the bails are raised to pull out the spout and unscrew the closure central part, providing a degree of anti-tamper security. However it is still possible to “pop off” the entire cap/spout assembly from its snap-fit connection at the container neck, without breaking the frangible links.
A further problem is that the range of elastic deformation over which such a snap-engageable ring will provide satisfactory holding and energising force to the spout/neck joint is quite limited. Blow-moulded containers often exhibit large variations in their neck dimensions and container necks of a nominally standard size made by different manufacturers using different equipment can in fact also vary considerably in their critical dimensions, so that snap-fit all-plastics spout closure and joint constraint rings as described above will not perform satisfactorily for all the containers of a nominally identical neck size.
Such snap-fit closures also rely to some extent on the deformation of the container neck for ease of fitment. Metal container necks formed e.g. in pail lids and drum ends are relatively stiff, and this can lead to difficulties in applying the snap-fit closures, particularly if the container necks concerned are somewhat oversized. A more versatile and easier to fit plastics stabilising/enegising band for a spout/container joint or lid/container joint is therefore desirable.
A plastics overseal for a drum closure plug is known which comprises a disc-like or short cylindrical housing having an inwardly projecting peripheral flange at its lower end, by which the overseal is secured around a closure plug having an outwardly projecting peripheral flange. The overseal is axially divided along a diameter into two halves, connected at one end of the divide along an axial web-type hinge. Snap-fittingly interengageable fastener parts are provided on the overseal side wall at the other end of the divide opposite to the hinge, so that the overseal can be opened up to fit over the plug and then closed and secured with its inwardly projecting flange trapped beneath the plug flange. The overseal is not constrictable about the plug, but is instead a relatively loose fit.
Cable ties are also known which can be used to hold cables or the like in bundles, but these ties are not used, nor are they suitable for use, in container/spout joints. For example their fastening means are relatively bulky, making them difficult or impossible to fit around a recessed spout/container joint. They also lack security, and can be opened using a screwdriver or the like, without damage and hence without tamper indication.